A federal judge in Florida struck down a key element of the Obama administration's health care law, ruling that a requirement for Americans to buy health insurance is unconstitutional and the rest of the law cannot stand without it.

While Vinson ruled the law is unconstitutional, he does allow the government to continue implementing it pending appeal.

The ruling marks the first time a federal judge has said the entire law should be struck down.

"I must conclude that the individual mandate and the remaining provisions are all inextricably bound together in purpose and must stand or fall as a single unit," the judge ruled.

Florida, joined by 25 states, brought the lawsuit challenging the Affordable Care Act, arguing that Congress did not have the authority to force an individual to enter a marketplace or buy a particular good or service.

The states argued that while Congress could regulate economic activity, it could not regulate "inactivity" such as an individual's choice to refrain from buying health care insurance.

"It is not hyperbolizing to suggest that Congress could do almost anything it wanted," he wrote.

Justice Department lawyers had defended the law in court, arguing that the constitution gives Congress the authority to regulate interstate commerce, and that includes the health care costs of the uninsured, which reach $43 billion annually.

But the judge disagreed.

"Every person throughout the course of his or her life makes hundreds or even thousands of life decisions that involve the same general sort of thought process that the defendants maintain is 'economic activity,'" Vinson ruled.

Florida Attorney General Pam Bondi called the ruling "an important victory for every person who believes in the freedoms granted to us by our Constitution."

"This proves that the federal government requiring Americans to purchase health insurance is in fact unconstitutional," she said.

The Justice Department announced it will appeal today's ruling.

A senior administration official called the decision an "outlier" and said that the law will continue to be implemented pending the appeal process.

Today's decision means that two federal judges have upheld the law and two have ruled against it.

The case is expected to reach the Supreme Court in about two years' time.

While there are currently several challenges to the health care law from states and private parties playing out in federal courts across the country, this particular law suit was being carefully watched by constitutional experts because of the number of states that had joined the challenge.

"The cases involving the states have a little more gravitas because they involve institutional actors that squarely represent the question of federal over state power," Santa Clara University law professor Bradley Joondeph said.

So far the cases have split down ideological lines, with judges who were appointed by Democratic presidents upholding the law, and judges nominated by Republicans striking down the individual mandate.

"As a general matter in the full universe of cases in federal court, the politics of a judge doesn't matter," Joondeph said. "But in a case like this where the law is not clear and the ideological stakes are so high, judges are inevitably influenced by their political leanings. All human beings are."